Ladder-jack.



PATBNTED MAR. 17, 1908.

o. c. A. BLOCK.

LADDER JACK.

APPLIOATION I'ILBD JULY 1, 1907.

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OSCAR G. A. BLOCK, OF DAVENPORT, IOWA.

LADDER-JACK.

Specification of Letters Patent.

Patented March 17, 1908.

Application filed July 1, 1907. Serial No. 381,817.

T 0 all whom it may concern:

Be it known that I, OSCAR O. A. BL'ocK, a citizen of the United States of America, residing at Davenport, in the county of Scott and State of Iowa, have invented a new and useful Ladder-Jack, of which the following is the specification.

My invention relates to improvements in ladder jacks in which a frame is employed which has one end hooked upon or over a round of a ladder and the other end sup ported by chains, or other means, and which support a plank or staging upon which work men may stand while painting houses or any work requiring staging.

The objects of my invention are to provide a simple, secure and easily transportable and adjustable support for a plank or staging. I attain these objects by the mechanism illustrated in the accompanying drawings, in which Figure I is a side elevation of the jack in position to support a plank but showing the nearer sidepost of the ladder removed and the jack in the position it would be where the plank and jack are placed on the side of the ladder opposite. the side which rests against the building or other structure supporting it. Fig. II shows a similar view but with a plank and jack on the same side of the ladder as the structure supporting the upper end of the ladder. Fig. III is a plan view of the jack showing the plank in dotted lines. Fig. IV is a side view of the jack with plank and chains removed. Fig. V is a detail of the brace for the inner ends of the supporting rods or frame. Fig. VI is a front elevation of the ladder with a jack attached.

Similar letters refer to similar parts throughout the several views.

The frame of the jack consists of a U- shaped rod B, of iron or other suitable material bent to form three sides of a rectangle with a hook B formed upon each end of the rod. The hooks B are brought close enough together and formed of a size suitable to hook to or engage the opposite ends of one round of a ladder. A cross brace 0 having a loop or eye 0 formed at the middle of it, is secured to the ends of the supporting rod B, near the hooks.

A twin or double eye 0, is secured to the middle of the outer end of the supporting frame B, and a chain 0 has one end secured to the twin or double eye 0, and its opposite end secured in the loop or eye c at the middle of the cross brace 0 and may be secured to the cross brace 0 by a link or by a snap D, as shown in Fig. V. Another chain O, has one end secured to the twin or double eye 0, at the outer end of the supporting frame B, and its other end'secured to an S-shaped hook 0*, which engages another round of the ladder. A plurality of these jacks are designed to be used with two or more ladders and a plank b, has one end resting upon the jack secured to one ladder and its opposite end resting upon a jack secured to another ladder. The plank 1), passes under and is held by the chain 0 but the chain 0 is adjusted with slack enough to allow the plank to be moved laterally toward or away from the ladder as desired.

The chain C, can be adjusted to any desired length by moving the hooks 0 from one link to another, but in practice it will be found that the chain C, can be shortened sufficiently for practical purposes by twisting it a few turns before hooking the hook 0 over the round. This form of jack has many advantages over any form heretofore in use. It is simpler, more easily put on and removed, more easily adjustable and can be attached to either side of the ladder, and can readily be entirely removed from the ladder. It can be secured to ladders standing at different angles.

The improved construction shown provides a safe support for a plank or a staging upon, which painters or other men working upon houses can stand. and one which is readily adjustable andeasily removed from one position to another. While certain forms of supports have been in use heretofore, none of them offer the advantages obtainable by the invention above described.

In operation,- the plank is ordinarily. secured to the supporting frame B, by the chain 0 before the su ortin frame is attached to the ladder. The ladders are then set up against the wall and the hooks upon the inner end of the supporting frames B, are hooked over rounds of the ladders at about the same level. The hooks 0 are then hooked over rounds of the ladders above the supporting frame and also hooked into links of the chain C, to make it the proper length to hold the outer edge of the plank substantially level with the inner edge. In taking down the staging, the hooks on the inner ends of the supporting frames are first disengaged and the plank with the supporting frames attached allowed to hang by the hooks 0 which are then removed and the plank lowered to the ground by the chain C, or other- Wise as desired.

What I claim and desire to secure by Letters Patent, is

1. A ladder jack comprising a U-shaped frame having hooks and a cross brace formed with a central eye, at its ends, a chain extending lengthwise of the frame and having its ends secured to the central eye of the cross brace and to the outer end of the frame, respectively, for holding a board transversely of the frame, and a supporting chain secured to the outer end of the frame and provided with a hook at its outer end.

2. A ladder jack comprising a U-shaped frame having hooks and a cross brace, at its ends, a double eye through the lower eye of Which the outer end of the frame is passed, a supporting chain secured to the upper eye of the double eye and provided with a hook at its outer end, and a chain extending lengthwise of the frame and having its ends secured to the cross brace, and to the upper eye of the double eye, respectively, for holding a board transversely of the frame' 3. A ladder ack comprising a U-shaped frame'having hooks, and a cross brace formed With a central eye, at its ends, a double eye through the lower eye of Which the outer end of the frame is passed, a supporting chain se-,

cured to the upper eye of the double eye and provided With a hook at its outer end, and a chain extending lengthwise of the frame and having its ends secured to the central eye of the cross brace and to the upper eye of the double eye, respectively, for holding a board transversely of the frame.

OSCAR C. A. BLOCK. 

